Thursday, February 11, 2016

The Spectre of the iPhone Spectroscope

Image Credit: My first spectra with the Cannon 550D

Colour, the final frontier. Of course if you want to be a "real astronomer" the visible spectrum is only a small part of the story. Much of our knowledge of astronomy comes from spectra and radio astronomy.

At the 2014 NACAA Conference I was drooling over Ken Harrison's amazing Spectroscopes after his talk and made the comment, it would seem so unfair to buy one off the shelf without going through the pain [Learning Experience] of trying to build one myself. So true to my word I had a go at the basic process of "getting colour".

I wasn't too concerned at this stage about quality, just some rational experimentation with the process to gain a deeper understanding. So I went off to the local hardware and bought a few bits and pieces and broke up a cd (carefully) and peeled the film back. At this stage it was unclear to me whether Barry Manilow CDs or Justin Beiber CDs would provide the best high or low resolution diffraction grating. Carefully pulling apart a three blade razor and using two of them to create a slit, challenged my dexterity. After tinkering away for a couple of sessions over a few weeks, I managed to come up with this monstrosity. Splits the light, can see colour, but probably absolutely useless for real science, but fun to play with and demonstrates the principle of a spectroscope well.

The first place to start this journey is with Ken Harrison's book Astronomical Spectroscopy for Amateurs. It is well written but looks quite daunting when you first pick it up. However if you work through it bit by bit, its a great book with everything you need to know.

Feeling a little more confident, I invested in the next logical step - a Star Analyser 100. This is the entry level standard for beginners, and produces fine results as we'll see.

After passing it around the family to have a look at the cool effects looking at the ceiling lights, I lost the plot and departed from Ken's careful, meticulously presented steps, with the outrageous thought - I wonder how this baby would go on an iPhone! I am constantly amazing at STEM events and star parties how the "younglings" immediately are so amazed by what they see through the eyepiece they want to whip out the smartphone and take an image home with them.

Surely it couldn't possibly work. After all the iPhone 6 sensor is only 4.8mm by 3.6mm, it has a focal length of 29mm and is f2.2. But its an 8M pixel camera (said my evil twin subconscious), your Fingerlakes PL11000M is only 11M pixels so its only 3000 less pixels, how bad could it be....hang-on whats the pixel size ...ah 1.5um versus 9um, interesting. So the sensor is 3264 x 2448, interesting ..... iPhones do take good photos......on a sunny day.....not in the night sky. This went on for a while!

So in the end there was nothing else to do but try it, and learn from your spectacular mistakes!

The next problem was how do I keep the shutter of the iPhone open for long enough to take star photos on a guided telescope - this is not the moon, a great iPhone target normally, but with the standard phone settings thats all the iPhone seemed good for. So channeling my teenagers I thought, there must be an app for that. To my amazement I could not only find one, there was a choice of several apps and 645 Pro could even do it with an Kodak Ektrachrome 64 film "feel to it". NOTE: to those born after the 90's, can you imagine only getting 36 images on one roll of film and not being able "to delete the bad ones" until after you had paid $25 and sent it off to the developers and had it returned to your letter box. In those days the lens ONLY pointed away from you - THE HORROR! Anyway I digress. 645 Pro basically turns your iPhone into a simulated DSLR and enters the workflow of the photography before any JPEG compression. You can set ISO and shutter speed, bracket exposures do all sorts of things that you can do on a DSLR.

With my trusty new app, my camera adapter, my star analyser, a 25mm eyepiece, I was ready for action.

I started on Canopus, after the bright star align was completed, but was more interested in Betelgeuse. After slewing and removing the eyepiece and inserting my newly built contraption, I was sure it was the world's first ultra-low resolution Spectroscope. A quick google search showed I was in fact two years behind the times. However to my amazement I had colour and with some detail, I got "lines" as well. I messed around trying different settings and moved over to Betelgeuse and took some more and put the 2 x barlow in front of the Cannon 550D and tried that for comparison purposes. (See image - top of page)

As an experienced "normal" (although I know you are wondering by now how "normal" that is) astrophotographer I was keen not to overexpose the image - Hmmmm - I have no idea what the well depth of an iPhone sensor is, lets just take as many as we can and see how we go.

I must say the results amazed me. Punching the air in victory, my evil sub-conscious dredged up an "I am invincible" [from the Bond film Golden Eye].

By now it was approaching midnight, and quietly tiptoeing around my back yard I packed up the telescope and headed inside. Damn ... I was so excited, I forgot to change the camera settings to save in dRAW/TIFF - back to the drawing board! Well at least I have some nice completely useless JPGs, but what an exercise that was, one I know I will be able to use again and again.

Friday, February 5, 2016

Certain of uncertainty for near earth asteroids

In my continuing efforts to de-mystify the art of Asteroid Astrometry, I thought I'd follow up last week's article on about 2016 BE with a deeper examination of the Uncertainty parameter when its listed in orbital elements.

This week there is some attention on 2013 TX68 which will possibly make a record close pass of 11,000 klms or possibly be 40 times further away than the moon on March the 5th. I can see that puzzled look on your face ;-) 2013 TX68 is also a Virtual Impactor in 2017, a term we discussed last week.

So firstly lets get some perspective on this uncertainty thing.

2011 CF66 was also listed as a virtual impactor for Feb 2nd 2016, it didn't hit us, no-one was worried if it would, and in fact no-one has any idea where it actually is. It is only a tiny asteroid about 3-9m in diameter and wouldn't have done any damage even if it did. In fact there are 20 other virtual impactors listed in the Risk Table this year, the next one might approach on Feb 18th, is 2009 VZ39, and is slightly smaller than 2013 TX68. 2009 VZ39 is also in the daytime sky and not observable for follow up and further confirmation. I only highlight this to emphasise the point here - all asteroids once they are discovered need to be tracked for sometime, to improve the precision of the orbit before any pronouncements about where they are going to be at a certain point in time. The difference between 2013 TX68 and 2009 VZ39 for example is that 2013 TX68 was observed for 31 data positions (astrometry) over 3 nights where as 2009 VZ39 was observed on only one night with 8 astrometric data positions. If you look at the orbital elements for 2013 TX68 the uncertainty parameter is listed as 7, where as for 2009 VZ39 there is not even enough data to start that calculation. For 2011 CF66, there is a 1.1e-8 chance of a collision between 2016 and 2114, so its mathematically possible, but highly unlikely.

NASA/JPL produced this nice graph with it's press release this week which illustrates the point well.

Image Credit: P. Chodas (NASA/JPL)

What you see is a graphical representation of the "error bars" or the zone of uncertainty, based on the orbit elements that we currently know. This asteroid will be picked up again in future surveys and the zone of uncertainty will reduce further.

Uncertainty Parameter is quite a complex calculation, but it essentially always starts off being a "9" and reduces over ensuing months as more data is collected. Uncertainty is a table of the "Runoff" of arcsecs per decade and Level 7 just means essentially there will be less than 33,121 arcsecs of "runoff" over the next decade. You can think of this as being: in a decade the place to look will be 33,121 arcsecs bigger than the range of uncertainty we need to factor in when we look for it now.

Many of the "click-bait" bloggers and conspiracy theory followers regularly confuse Uncertainty with the Torino Scale - they shouldn't, as even WIKIpedia has a great explanation of the Uncertainty factor, however they google "Asteroid rating 7" and get a hit on what the Torino Scale is and confuse the two, without doing any further investigation. The Torino scale is a risk weighted table and ALL current Virtual Impactors are listed as Torino Level 0. The virtual impactors that are listed have "potential" collisions over a range of years and are only there because we largely don't have enough data yet to remove them.

Asteroid Apophis (99942) 2004 MN4 briefly shot up the Torino Scale to a record high Level 4, before subsequent radar imaging and 4452 observations over 10 oppositions reduced its Uncertainty Parameter to 0 and its Torino Level to 0, with an asterisk that it needs to be carefully watched. Asteroid Apophis will be a naked eye object on April 13th 2029 when it makes a very close but HIGHLY CERTAIN pass of the earth. This level of certainty is only refined by many hundreds of hours of dedicated work from professional and amateur astronomers.

Lastly, Uncertainty should not be confused with don't know, don't care, have no idea what we are doing. Its just a case of not YET having enough data, more needs to be collected.

Friday, January 29, 2016

Asteroid 2016 BE Virtual Impactor for now in 2053

UPDATE 31/1/2016: The 2053 pass has been eliminated as a risk. There are still 5 virtual impacts from 2076 - 2111. These will also likely be removed as the precision of the orbit is improved.

Tonight, tracking potential virtual impactor Asteroid 2016 BE. Its a 79m wide Asteroid discovered on Jan 16th by the Catalina Sky Survey(703).

78 positions have so far been reported from 18 different observatories, including both H06 and I89, the iTelescope.net observatories. I managed to grab another 3 positions tonight. The asteroid is starting to speed up (in terms of relative velocity against the background stars) and tonight is moving quite quickly at 19 Arcsecs per minute. As a result of the fairly bright magnitude and the fast speed, you need to take as short an exposure time as possible. However the full moon is still pretty bright I had to use 30 sec images which means the asteroid is still slightly streaked. I have used a stacking technique to make sure my residuals are still reasonably good (given it is travelling at fairly high speed).

So what actually is a "Virtual Impactor". As asteroids are tracked the length of the recorded "arc" increases - now 10 days for 2016 BE. Of course the level of precision for future positions of the asteroid increases the longer the "known arc" and therefore the ability to determine future positions of the asteroid improves as the "zone of uncertainty" reduces. As long as the "zone of uncertainty" overlaps the earth's future orbit position, the object is listed as a virtual impactor for that pass. This happens from time to time without much concern, because as the precision of the orbit improves with more observations, the object usually drops out of the risk table quite quickly.

Whilst the asteroid will make a moderately close pass in the first week of February at 5.7 Lunar distances, its important to understand that the "virtual impact" currently listed in the Sentry Risk Table is for the 3rd February 2053 .... NOT ON THIS PASS!!!! As you would expect the "zone of uncertainty" for 2053 is much large than the "zone of uncertainty" for next week. So it will take many further observations before it is (most likely) removed from the risk table. Its current risk table score of Torino-0 just means that at this point the chance of a collision in 2053 has not been able to be eliminated at this stage.

Measured position:

K16B00E KC2016 01 28.46044 12 04 01.15 +65 50 49.0 16.9 R H06

K16B00E KC2016 01 28.46319 12 04 09.44 +65 49 54.8 17.3 R H06

K16B00E KC2016 01 28.46604 12 04 18.01 +65 48 58.7 17.4 R H06

Wednesday, December 9, 2015

Variable Star workshop on KIC 8462852 at VSSEC

A big shout out to the Victorian Space Science Education Centre and Telescopes in Schools program who hosted me yesterday running a variable star workshop with students and science teachers. The staff were magnificent and the centre is a real credit to all involved.

The Mars Science Mission experience is second to none and has to be seen to be believed. My workshop involved an introduction to variable star astronomy including a worksheet exercise of basic Visual Observation Photometry, culminating with the class comparing their "visual" observation with a highly precise VPhot measurement straight from one of iTelescope.net's Telescopes.

Result: The class determined that KIC 08462852 was at its long term photometric brightness of 11.87 and provided another 32 data points to the AAVSO's long term study of the star. The target is subject of Dr Tabitha Boyajian et al's Paper KIC 8462852 - Where's the Flux (WTF) a Planet Hunter target from the Kepler Mission that exhibited some strange and difficult to explain behaviours.

In a week where Australia's STEM Future was front and centre, it was great to be out and about doing something about it.

Thursday, October 15, 2015

Asteroid 2015 TB145 (PHA) close and bright flyby Oct 31

UPDATE: Oct 31st, 2015. Live coverage of Asteroid 2015 TB145.

Image Credit: P.Lake 10 Sec image from U69 T24 - travelling at 115 arc"/m at PA 35.4 07:00 UT (Available for media use with attribution to this blog)

Compare the two images - Above a 10 sec image, Below a two minute image which was stacked for movement of the asteroid.

UPDATE: Oct 31st, 2015 - From the NASA Press release this morning the amazing radar images have shown a dark dead comet,(and I am not making this up) looks not unlike a skull. The radar run went well getting down to a resolution of 7 meters per pixel. Its interesting those depressed areas are likely impact craters or collapsed areas from which the jets emerged when the comet was active. Recent studies of 67P by Rosetta have shown collapsed areas on Comet 67P where jets seem to originate from. This comet has been long dead, some studies have already been done to check for past meteor showers originating from its orbit - see the post on the SETI Institute Blog. Also from the press realease: "NASA values the work of numerous highly skilled amateur astronomers, whose accurate observational data helps improve asteroid orbits....". I hope to have more images tonight (weather permitting) - stay tuned.

Image credit: NAIC-Arecibo/NSF

UPDATE: Oct 27th, 2015 - Great set of images last night in the pre-dawn sky from New Mexico. The asteroid has brightened to Mag 15.8 and its apparent speed across the sky is starting to increase as it gets closer. [Also I should probably point out the faint halo you may be able to see is due to the strong moonlight reflecting off some dust on the primary mirror - the full moon was only 36 degrees away]

UPDATE: Oct 24th, 2015 - Finally got some images. The asteroid has brightened considerably to Mag 16.8/9 ish. No signs of cometary activity at this point. Its moving at 0.39arc"/m in a 120 sec image (so 0.78arc" in the image)and the pixel plate scale is 0.53 arc"/pixel so you can see a hint of softness on the trailing side. Definitly no cometary activity though - that's as close as I can go to getting it as sharp as you can get it.

Image Credit: P.Lake 2015 TB145 9x120 secs on the 0.7m Burnell, Cannon, Leavitt Telescope (BCL) T27 at Q62, SSO.

UPDATE: Oct 22nd, 2015 - Getting frustrated, the observatory has been closed due to bad weather for 4 nights.

UPDATE: Oct 17th, 2015 - NASA have updated details of the planned radar runs and expect to be able to get images with a resolution of 2 meters per pixel, they expect it to be the best radar run of the year. Also one other interesting aspect is the Tisserand parameter has been calculated at 2.937 which is just lower than the theoretical "boundary" (of 3.0) between Asteroid and Jupiter Family Comets. The other target of a radar run on 29th is 2009 FD, a well studied Apollo Asteroid, has a Tisserand parameter of 5.295. The seeing was a bit poor on the 14th so the image wasn't strong enough. The relative speed (across the camera chip) will slow to only 0.17 arc"/min on the 19th so I'll be able to stack the images really deep and get a good look at it. If the seeing is better tonight we might even get some more detail. I did look a bit fuzzy the other night but as you can see in the video the satellite that trailed through was very fuzzy as well - so I'm not reading to much into that at the moment.


Image/Video Credit: 2015 TB145 from H06, 12 x 180 sec exp stacked 4x3, 0.5m Planewave October 14th - P.Lake

A couple of times a year, the asteroid surveys throw up a surprise, with a large asteroid approaching very close to the Earth, with little advance notice. After last week's blog post about the Blogsphere overeacting to an Asteroid that astronomers knew about for 15 years passing at 65 Lunar Distances (LD), the "surprise" of course had to happen this week.

This will be an interesting two weeks, as Asteroid 2015 TB145 will cruise by Earth just outside 1 Lunar distance (1.3 LD). The asteroid is a target of the Arecibo Observatory (that big antenna that rose out of the lake in the majestic James Bond scene), and to get some really great radar tracking and detailed images, the ephemeris and position of the asteroid needs very high precision.

To give you an idea of the type of imaging to be obtained (see below), a similar situation occured last year for 2014 HQ124. These were some of the best radar images ever recorded, and some of my data was used to refine the orbit for targeting on that occasion.

Image Credit: Asteroid 2014 HQ124 Radar images from Goldstone - NASA/JPL

This asteroid is twice as big (between 290 and 650 meters diameter - most astronomers are calling it about 480m) and twice as close as 2014 HQ124, so you can only imagine how good the images should be. Professional Observatories and amateur astronomers will be tracking it closely to improve the precision of the orbit as it approaches.

I was quite chuffed when tracking 2014 HQ124 that my light curve had a few bumps in it and I made the call it was "not round" which was subsequently confirmed by the radar images.

So who knows what the next two weeks will turn up? What we know at this stage is that is going to be quite bright and could be visible in binoculars. Also its speed is very fast, but its moving slowly across the images at the moment as you can see, because of the angle its approaching us at. As it makes its close approach its going to do a nice "flyby" of the Crab Nebula M1 for Northern Hemisphere viewers on Oct 29th/30th Ian Musgrave has details on his blog shortly.

So stay tuned, I'll be following it closely and providing some regular updates.

Wednesday, October 14, 2015

Rustling up more services for the bush - Sky Muster NBN1A Launch

Image Credit: P.Lake 60 Sec Luminance on Takahashi FSQ106 T12 at Q62

I like the name ...... Sky Muster, it taps into the rich heritage of the Australian cattlemen and women, stockmen, jilleroos, even the Banjo Patterson text "Man from Snowy River". Its all about rustling up some more broadband and access for the people of rural Australia and lifting the capability of rural Australia. Some people would see living remotely as advantageous, peace and quiet, the great outdoors, but the tyranny of distance has always meant is much harder to provide services - and today services means data access.

So I love the name, its certainly better that the Argentinian satellite on the same flight, Arsat-2 (just making sure I spelt that right .... yes I did) ;-)

Sky Muster or otherwise known as Satellite NBN1A was launched on Sept 30th on an Ariane 5 flight VA226 and took up its spot as a Geo-Stationary communications satellite designed to bring high speed broadband to Rural Australia.

There is a great animation here of the launch vehicles and satellites from the KNews team in Germany......

Well this is as close as Australia has to a Space Program at the moment, (in fairness we do lots of cool stuff from the ground).

I saw a note earlier that the satellite had successfully deployed it's solar panels and was healthy and well, so I thought I take a photo of it to celebrate. So, logging into the Internet of Everything (IoE), and using a remote telescope at Siding Spring Observatory I was able to grab a few shots of it and a few of its neighbors.

In the early part of the evening after the sun has set and the satellite is still in the sunlight (as its 36,000 Klms up) it is possible to grab some photos with a powerful telescope, kind of like photographing a bus from 36,000 Klms - difficult, but it can be done!

Those large solar panels are giving of a bit of reflected light and brighter than the Russian Express-AM5 which is 400Kgs heavier. You can also just faintly make out the Himawari 8 and the much smaller Beidou Chinese Sat-Nav satellite as well. You can also see another (non-geostationary) comms satellite cutting across the image as well.

The images are 60sec exposures from a Takahashi FSQ Petzval 106mm refractor telescope with a large field of view. The background stars look still and the movement of the geostationary satellite of course reflects the speed of rotation of the earth. They are hooting along quite quickly.

I trust the cattlemen, shepherds, wheat farmers and all rural folks get great use out of this investment in Sky Muster - I just had to take a photo of it. Congrats again Andy and all the NBN team.

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